Projectile flight altering apparatus
A mechanism to alter the flight path of a projectile after launch. A plurality of fins are disposed around the projectile and are held in place by one or more caging wires, depending on fin design. In one embodiment, auxiliary fins are connected to adjacent main fins which are held in a stowed position. When released, the fins deploy and present a continuous surface to the airstream for maximum braking action. In another embodiment, each fin is divided into fin segments which are individually deployable to alter the spin or course of the projectile by deflection. Additionally, all of the fins may be deployed to provide a braking action. All of the fins are tied together to distribute and reduce encountered loads when deployed.
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The inventions described herein may be made, used, or licensed by or for the U.S. Government for U.S. Government purposes.
BACKGROUND OF INVENTIONIt is often desired to modify the trajectory of a projectile (including missiles) after it has been fired. Conditions such as wind, temperature variations, precipitation, aiming error etc. can cause the projectile to deviate from its intended course, as determined by remote tracking of the projectile or on-board guidance systems. To modify the trajectory, mechanisms are used which are fit onto the projectile and deploy aerodynamic tabs, or fins, while in flight, to impart a corrective action to the projectile. Such corrective action may consist of braking, spin modulation and deflection of the projectile, each action being achieved by a single independent mechanism.
Such mechanisms utilize fins which pivot or eject from a closed inboard position to an open position whereby they extend radially around the projectile body. The pivoting means are subject to breakage when deployed into the airstream and in order to prevent such breakage the fins and pivots must be relatively massive and are typically of heavy machined metal. When deployed as a braking mechanism, the fins become spaced apart so as to present voids between fins, which require the fins to be larger to compensate for the voids. In one embodiment of the present invention an arrangement is provided which presents a continuous fin surface around the periphery of the projectile, with light-weight fins, to increase effective fin area and thus enhance braking action.
In other types of flight altering mechanisms, fins are deployed to spin modulate or deflect the projectile. They cannot, however, apply a braking action without deploying a second independent mechanism. In other embodiments of the present invention arrangements are provided that can selectively and sequentially accomplish spin modification, deflection, as well as braking as a final adjustment, if required.
SUMMARY OF INVENTIONA flight altering apparatus for attachment to a projectile, in accordance with the present invention, includes a frame member and a plurality of fins each connected to the frame member by a pivot and surrounding the projectile. A caging arrangement is provided to maintain the fins in a stowed condition and is operable, when activated, to allow deployment of the fins. A coupling means connects adjacent fins to evenly reduce and distribute aerodynamic loads on the fins and pivots when deployed, and ensure simultaneous and limiting deployment during the flight of the projectile.
The invention will be better understood, and further objects, features and advantages thereof will become more apparent from the following description of the preferred embodiments, taken in conjunction with the accompanying drawings, in which:
In the drawings, which are not necessarily to scale, like or corresponding parts are denoted by like or corresponding reference numerals.
If the projectile 10 is being tracked by a remote tracking system, the electronics section of the forward portion 12 may receive commands from the tracking system to cause deployment of the fins. If the electronics section is self-contained with inertial guidance or GPS circuits, as well as a computer, then the electronics section itself may initiate deployment of the fins without external commands.
One embodiment of the present invention is illustrated in
The fins are carried by a frame member 22, which, in
A typical main fin 18, with a portion broken away, is illustrated in
As seen in
In
As will be seen, the caging arrangement includes, for example, at least two, and preferably three caging wires connected to respective tightening bolts 68, 69 and 70 on forward ring 23. A more detailed view of the underside of a typical fin 58 is illustrated in
Caging wire 88 passes through notch 85 in side flange 77 and through aperture 80 in side flange 76 and secures fin segment 60 so that it will not deploy until caging wire 88 is released. Similarly, caging wire 89 passes through aperture 83 in side flange 77 and through notch 82 in side flange 76 and secures fin segment 61 so that it will not deploy until caging wire 89 is released. A caging wire 90 passes through an apertured stub 92 on the undersurface of central fin segment 62, and through notches 81 and 84 in side flanges 76 and 77. With this arrangement, either fin segment 60 or 61 may be selectively deployed, by releasing either caging wire 88 or 89. To assist in this deployment, and as indicated in
In
If a braking action is desired, either after a spin modification or in lieu of spin modification, then all caging wires 88, 89 and 90 of
For example, if a spin modification is desired similar to that resulting from the fin deployment in
Six caging wires (not illustrated) are used to deploy selected fin segments and fins. A first caging wire connects fin segment 60 of fin 58-12 to fin segment 61 of fin 58-6. A second connects fin segment 61 of fin 58-12 to fin segment 60 of fin 58-6. A third connects fin segment 61 of fin 58-3 to fin segment 60 of fin 58-9. A fourth connects fin segment 60 of fin 58-3 to fin segment 61 of fin 56-9. A fifth connects all central segments of fins 58, and a sixth connects all of fins 120. The fifth caging wire may be eliminated by connecting the central segments 62 with all the fins 120.
In a similar fashion, and as indicated in
Partial braking may be achieved by deploying all fin segments 60 and 61, as in
It will be readily seen by one of ordinary skill in the art that the present invention fulfills all of the objects set forth herein. After reading the foregoing specification, one of ordinary skill in the art will be able to effect various changes, substitutions of equivalents and various other aspects of the present invention as broadly disclosed herein. It is therefore intended that the protection granted hereon be limited only by the definition contained in the appended claims and equivalents. Having thus shown and described what is at present considered to be preferred embodiments of the present invention, it should be noted that the same has been made by way of illustration and not limitation. Accordingly, all modifications, alterations and changes coming within the spirit and scope of the present invention are herein meant to be included.
Claims
1. A flight altering apparatus for a projectile, comprising:
- a frame member;
- a plurality of fins each connected to said frame member by a pivot and surrounding said projectile, said plurality of fins further comprising: a plurality of main fins; and a plurality of auxiliary fins, each connected to two adjacent ones of said main fins to present a total fin surface to the airflow, when deployed, which is continuous and extends 360° around said projectile without any voids, so as to provide for maximum braking action;
- a caging arrangement to maintain said fins in a stowed condition and operable, when activated, to allow deployment of said fins;
- coupling means connected adjacent ones of said fins to evenly reduce and distribute aerodynamic loads on said fins and pivots when deployed during flight of said projectile; and wherein:
- each said main fin includes side flanges;
- each said side flange includes a slot;
- each said auxiliary fin includes side flanges;
- each said side flange of said auxiliary fin fitting through said slot in said side flange of an adjacent one of said main fins.
2. A flight altering apparatus for a projectile, comprising:
- a frame member;
- a plurality of fins each connected to said frame member by a pivot and surrounding said projectile;
- a caging arrangement to maintain said fins in a stowed condition and operable, when activated, to allow deployment of said fins;
- coupling means connected adjacent ones of said fins to evenly reduce and distribute aerodynamic loads on said fins and pivots when deployed during flight of said projectile; and wherein:
- each said fin has a triangular central segment and first and second triangular fin segments contiguous with said triangular central segment and pivotable about said central segment along first and second hinge lines.
3. Apparatus according to claim 2 wherein:
- said caging arrangement includes a first wire connected to all said first fin segments and a second wire connected to all said second fin segments for independently deploying said first fin segments and said second fin segments.
4. Apparatus according to claim 3 wherein:
- said caging arrangement additionally includes a third wire connected to all said central segments.
5. Apparatus according to claim 2 wherein:
- said coupling means is a wire connecting adjacent ones of said fins.
6. Apparatus according to claim 3 which includes:
- a spring member attached to an end of said fin to assist in deployment of said first fin segment or said second fin segment.
7. Apparatus according to claim 2 which includes
- a plurality of spring members, each connected to a fin for assisting in the deployment of said fin after said caging arrangement is activated to allow deployment of said fins.
8. Apparatus according to claim 2 wherein:
- said frame is circular;
- four of said fins are provided on said frame, two of said fins being diametrically opposed along a vertical line and the other two of said fins being diametrically opposed along a horizontal line;
- said caging arrangement being operable to selectively deploy predetermined combinations of said fin segments.
9. Apparatus according to claim 8 which includes:
- a plurality of other fins disposed on said frame between said fins between said fins with said fin segments; and
- said coupling means is a wire connecting adjacent ones of said fins.
10. A flight altering apparatus for a
- projectile, comprising:
- a frame member;
- a plurality of fins each connected to said frame member by a pivot and surrounding said projectile;
- a caging arrangement to maintain said fins in a stowed condition and operable, when activated, to allow deployment of said fins;
- coupling means connected adjacent ones of said fins to evenly reduce and distribute aerodynamic loads on said fins and pivots when deployed during flight of said projectile; and wherein:
- each said fin has first and second edges and a performed concave surface between said edges, adjacent an end thereof;
- said caging arrangement is operable to deform said fin to a convex orientation which is essentially conformal to said frame member;
- said caging arrangement being operable, when activated, to performed condition; and
- said coupling means is a wire connecting adjacent ones of said fins.
11. Apparatus according to claim 10 which includes:
- a plurality of spring members, each connected to a fin for assisting in the deployment of said fin after said caging arrangement is activated to allow deployment of said fins.
Type: Grant
Filed: Apr 5, 2004
Date of Patent: Feb 28, 2006
Assignee: The United States of America, as represented by the Secretary of the Army (Washington, DC)
Inventor: Joseph Pacchia (Mountain Lakes, NJ)
Primary Examiner: J. Woodrow Eldred
Attorney: Robert Charles Beam
Application Number: 10/708,977
International Classification: F42B 10/00 (20060101);